Flotation of ores



Patented Aug. 14, 1934 PATENT? OFFICE.

no'rA'noN or ones Ludwig J. Christmann, Jersey City, and David W. Jayne, Jr., Elizabeth, N. 1., asslgnors to American Cyanamid Company, New York,

N. Y., a corporation of Maine No Drawing. Application November 29, 1932.

Serial No. 644.8

20 Claim.

This invention relates to the concentration of ores and it has particular relation to concentration by the so-called flotation methods.

The invention has for its main objects the provision of a new class of promoting agents for froth flotation consisting of the xanthates of hydroxy ethers; the provision of a method of promoting the froth flotation of ores, such as the sulphides of copper, lead, zinc or similar metals involving the use of a xanthate of a hydroxy ether; the provision of a process of concentrating ores involving the use of a relatively inexpensive promoting agent, whereby exceptionally high concentration of ore is obtained with a minimum loss of valuable metals in the tailings.

It has heretofore been observed that when certain gangue containing ores, particularly the sulphide ores, such as the sulphides of copper, are reduced to a relatively fine degree of subdivision and then suspended in a carrier liquid such as water, they may be concentrated by subjection to a frothing action in the presence of a frothing agent such as pine oil. In this treatment the major portion of the ore rich in the sulphide of the metal tends to cling to the bubbles constituting the froth and may be removed, while the major portion of the gangue containing little metal values remains behind. It has also been observed that in this process of classification of the ore by froth flotation, better separations are obtained by the addition of a small amount of certain non-frothing materials termed promoters.

This invention involves the discovery that an entirely new class of compounds, the xanthates of the relatively complex ethers that contain a hydroxy radical, also are excellent froth flotation promoters. The type formula of compounds of this class may be represented as follows- The resultant xanthates prepared from such alcohols probably have the type formulaby alkylene radicals or residues, such as CHzCI-I: and appearing in the compounds ROCHzCHzOH, where R is a group selected from a class comprising alkyl and aryl radicals. However, it is also possible that it may be represented by groups 50 such as the types represented by the formulawhere R2 represents an alkyl group such as ethyl or butyl, or a group of the benzene series such as benzene, toluene or xylene. It may also be represented by the residues of di or tri ethylene glyggl and the like. Me is alkali metal (Na or Although, as previously indicated, all of these compounds are believed per se to be novel, the method of their preparation is substantially analogous to methods heretofore employed in the manufacture of xanthates of the simple alcohols. For example, in the preparation of the sodium xanthate of monoethyl ether of diethylene glycol, 5.5 liters of sodium hydroxide solution (.7669 grams NaOH per cc.) may be added to 13.5 kilo. of the monoethyl ether of diethylene glycol and so the mix stirred in an ice water bath until it assumes the form of a thick paste. To this paste 6 liters of carbon bisulphide are added slowly with continuous stirring and the stirring is continued for a period of about ten minutes after all of the carbon bisulphide has been added. The product is obtained as a yellow-brown syrup. Similarly the sodium xanthate of monobutyl ether of diethylene glycol is prepared from 5.5 liters of sodium hydroxide solution of the above indicated concentration with 16.5 kilo. of the mono butyl ether of diethylene glycol, the mix being stirred in an ice water bath until it becomes thick. In this case, 6 liters of carbon bisulphide are added slowly with stirring, and the stirring is likewise continued for a period of ten minutes after all of the carbon bisulphide has been added. The product is also a yellowish brown syrup. The xanthates thus prepared, as well as the other xanthates of the class included under the broad 100 scope of the invention, may be employed in combination with substantially any of the usual irothing agents, such as pine oil or similar materials.

The following constitute specific examples of 10 experiments conducted using the above indicated materials as promoting agents.

Typical ore sample.Copper ore consisting essentially of chalcocite with minor amounts of chalcopyrite and containing iron as pyrite.

Analysis Percent Copper 5.10 Iron 12.90 Insoluble 62.10

Preparation of are The ore as received was crushed to minus 20 mesh. A 1200 gm. sample of ore was ground with 600 cc. of water and lime in the ratio of four pounds per ton, for a period of ten minutes. The material showed the following screen analysis:-

Percent ore Results Test No.-

Product 0re%oiCu 5.19 4.87 5.18 5.00 5.14 Concentrate:

Grade in Cu contained 24. 25 18. 64 21. 43 27. 40 21. 4 oi Cu of ore recovered 31. 5 92 2 03. 5 78. 0 94. 2 Middlin s:

Grad c in Cu contained 12.48 2. 75 2.60 7. 24 3. 69 %oiCuoforerccovered 11.5 5.9 4.50 8.4 23 T ils:

8 Grade in Cu contained 3. 33 0.145 0.155 0. 0. 25s %of Cu of ore lost 57.0 1.9 2.0 l3.6 3.7

Total percent Cu recovered 43.0 98. l 98. 0 88.4 96. 3

In the above table the grade expresses the concentration of copper in the product. The percentage of copper of ore recovered expresses in Pe cent of the total proportion of copper of the corresponding ore, which is recovered in the particular product. The Total percent Cu recovered expresses in percent the proportion of copper of the ore recovered in the concentrate and middling.

In Tests 2, 3, 4 and 5 the sodiumxanthates of mono ethyl ether of ethylene glycol, mono butyl ether of ethylene glycol, mono ethyl ether of diethylene glycol and mono butyl ether of diethylene glycol were respectively employed as promoters. Test No. l was conducted upon a straight pine oil blank for purposes of comparison.

With a pine oil blank, only es% of the total copper was recovered. Where the xanthates of the ethers of a glycol were used as promoters, recoveries were much higher, ranging in fact from 86.4% in the case of the mono ethyl ether of diethylene glycol, to 98.1% in the case of the mono butyl ether of ethylene glycol Good recoveries may also be obtained by mixture of any two or more xanthates of the hydroxy ethers herein disclosed. or any one or more of the xanthates herein disclosed may be admixed in varying proportions, (e.g. 10 to 90%) with other flotation promoters such as sodium or potassium ethyl or butyl xanthates or thiazoles such as mercapto benzothiazole.

, It is to be understood that these agents may be used with the ground ores in their natural state, or in the case of certain non-sulphide ores, or native metals, it may be found advantageous to subject them to a process whereby they are coated with a superficial layer of sulphide which shows a particular affinity for the oil employed as a frothing agent. Therefore the term sulphide ore as herein employed includes oxide or other types of ores that are coated with or contain sulphides. Processes whereby ores, particularly the oxide ores which" do not lend themselves readily to froth flotation, are thus subjected to the formation of superficial coatings of sulphide, are wellknown in the art and since they per se do not constitute a portion of the present invention, it is not deemed necessary to discuss them in detail because any of the standard processes may be advantageously employed.

The new froth flotation promoters may be manufactured at slight expense from relatively simple and cheap primary ingredients and their use results, as previously indicated, in highly satisfactory separation of the ore from the worthless gangue. Therefore, they are highly desirable from a commercial viewpoint in processes of flotation. It is to be understood that they may also be employed in other processes where the use of a xanthate of the type disclosed is desirable. Therefore the invention is to be understood as including any use of the new materials.

Although we have shown and described only the preferred embodiments of the invention, it is to be understood that the latter is not limited to the specific forms disclosed but that various modifications may be made therein without departure from the spirit thereof or the scope of the appended claims.

We claim:

1. In the process of concentrating ores the step which comprises subjecting the ore to a froth flotation operation in the presence of a. frothing agent and a xanthate containing an ether grouping and containing no free OH groups, as a promoting agent.

2. In a method of concentrating copper ores the step which comprises subjecting the 'ore to a froth flotation operation in the presence of a frothing agent and a xanthate containing an ether grouping and containing no free OH groups, as at promoting agent.

3. In a method of concentrating sulphide ores or sulphide coated ores the step which comprises subjecting the ore to a froth flotation operation in the presence of a frothing agent and a xanthate containing an ether grouping and contain-= ing no free OH groups, as a promoting agent.

a. In a method of concentrating ores comprising subjecting the ore to a froth flotation operation in the presence of a frothing agent and a xanthate of a hydroxy ether of the type represented by the formula ROCH2CH2OH where R represents a group selected from a class comprising an alkyl or aromatic radical and containing no free OH groups.

5. In a method of concentrating ores, the step which comprises subjecting the ore to a froth flotation operation in the presence of a promoter M lt hahvllngsubstantially the following structural form where R and R1 are the same or difl'erent aliphatic or aromatic radicals or substituted aliphatic or aromatic or aryl alkyl radicals and Me represents a metal. 1

6. In a method 01' concentrating ores, the step which comprises subjecting the ore to a froth flotation operation in the presence of a promoter having substantially the following structural formula:--

in which R is aryl or alkyl or substituted aryl or alkyl and R1 is substituted alkyl and Me represents an alkali metal.

I. In a method of concentrating sulphide ores. the step which comprises subjecting the ore to a froth flotation operation in the presence of a promoter having most probably the following structural formula:

in which R is an ether group and R1 is an all phatic group and Me is an alkali metal.

9. In a method of concentrating ores, the step which comprises subjecting the ore to a froth flotation operation in the presence of a promoter having most probably the following structural formula:

5 a-o-m-o-E-sm in which R is a butyl group and R1 is a residue which comprises subjecting the ore to a froth flotation operation in the presence of a xanthate of an ether of a glycol.

11. As a new chemical compound the xanthate of mono-butyl ether of ethylene glycol.

12. As a new chemical compound the xanthate of mono ethyl ether of ethylene glycol.

13. As a new chemical compound the'xanthatc of mono ethyl ether of diethylene glycol.

14. As a new chemical compound the xanthate of the mono butyl ether of diethylene glycol.

15. In a method of concentrating ores, the step which comprises subjecting the ore to a froth flotation operation in the presence of a promoter having substantially the followin structural formula:

8 BOJh-O-E-S Me where R is an alkyl. aryl or arylalkyl radical and R1 an alkylene or aralkyl radical and Me represents a metal.

16. A process as defined in claim 15, in which R is aryl or alkyl or substituted aryl or alkyl and R1 is substituted alkylene and Me represents an alkali metal.

17. A process as defined in claim 15, in which R is an aliphatic or aromatic or arylallwl radical or substituted aliphatic or aromatic radical and R1 is an alkylene, arylalkyl or substituted alkylene or arylalkyl radical and Me is an alkali metal.

18. A process as defined in claim 15, in which R0 is an ether group and R1 is an aliphatic alkylene group and Me is an alkali metal.

19. As a new chemical compound the xanthate of a mono ether of an ethylene glycol with a hydrocarbon nucleus having from two to eight 7 carbon atoms.

20. As a new chemical compound the xanthate of a mono ether of an ethylene glycol with a hydrocarbon nucleus taken from the following group: ethyl, butyl, benzyl, tolyl, xylyi.

LUDWIG- J.- DAVID W. JAYNE, JR. 

